Black wants to execute a break with c7-c6, activating his pieces.
9. f1d3  9... f8e7 Both sides prepare \"short castling,\" or maybe I should say kingside castling since it's not so short here. 10. b4b5  10... c8d8  11. c1d1 There always comes a time when we have a \"normal\" position on the board, one in which the patterns are no longer as enigmatic as an exotic starting position with the king right between the two rooks, for example. This normality often appears after both sides have castled, arriving at a position that we can look at and, if no one told us, we might assume that it came from conventional chess. It wouldn't be impossible to imagine, looking at this position, that it had come from a Bird's Opening.